PHOENIX — At this rate, Francisco Rodriguez is going to have to change his nickname to Hit-Rod.

His numbers lately have been more like K-Fraud.

K-Rod was saved by a blown call by umpire Phil Cuzzi on Sunday, or else he would have picked up his third loss of the season and the Mets would have started the second half with four straight losses. He did earn his fifth blown save.

The Mets survived that game before last night’s 13-2 disaster in the desert, in which Rodriguez was not needed. But his struggles just can’t continue if the Mets have any hope of staying in the playoff chase.

Rodriguez (21 saves) has not reached the low point of Armando Benitez, but unless he turns it around, the Mets will be back in the same closer-less boat they were in the days when Benitez was in Queens.

In a string of six outings that culminated in Sunday’s debacle, K-Rod had a 7.11 ERA, and opponents batted .308 against him. He had more walks (6) than strikeouts (5) over that span.

“It looks like it’s all starting to catch up to him,” one scout who has followed the Mets most of the season told The Post last night.

“His velocity is down, his command is down and his curveball doesn’t have that sharp break. It’s more of a lazy curveball. He isn’t what he was, and his changeup isn’t as effective.”

The scout and others believe a career full of high-pressure innings may be catching up to K-Rod, who is in his ninth season.

“He has such a violent delivery,” another scout said. “It’s hard to keep all that together.”

Mets fans are frustrated watching K-Rod walk the razor’s edge every night. They have no confidence that he will get the job done. His Mariano Factor is zero. It also is frustrating to see ex-Met Heath Bell lead the majors in saves for the Padres.

With Mariano Rivera, it is a shock when he stumbles. Mets fans are expecting K-Rod to fall on his face, because nearly every save has been a K-Rod adventure.

Rodriguez is an extremely proud man, and that may be part of his problem.

“I watched him pitch this winter in Venezuela,” the first scout said, “and he was terrible.”

Rodriguez pitches winter ball every year back home in Venezuela because he believes he owes it to his countrymen. As a result of all that extra pitching, there is more mileage on Rodriguez, who set the major-league record for saves with 62 in 2008 while with the Angels.

When he was at his best, Rodriguez’s fastball lit up the gun in the 94-96 mph range. For most of this season Rodriguez has been in the 89-91 range.

Pitching coach Dan Warthen said last night that K-Rod’s gun readings on Sunday were excellent, and that he believes K-Rod is about to turn the corner.

“[Sunday] he had the best velocity we’ve seen from him all year — it was at 92-93,” Warthen said.

“I thought he made a couple of tactical errors. Certainly, when [Pablo] Sandoval is taking, you are not supposed to walk him. I was not displeased with K-Rod’s stuff. I didn’t like his pitch selection.”

K-Rod is one of those high-maintenance relievers in that his delivery is so violent.

“To maintain that delivery over the long haul is not an easy task” Warthen said.

Not being able to develop their own closers, the Mets have no one else to turn to in the bullpen. Though teammates are on edge when K-Rod takes the mound, they have not lost faith in him.

As one noted, “We have to believe in him, he’s our closer.”

K-Rod is a closer who needs a lot of work to stay sharp, as manager Jerry Manuel has said many times. When Rodriguez is challenged, he seems to step up his game. One scout believes he needs to throw his curveball more because his fastball is fading.

One way or another, K-Rod has to step it up. The Mets cannot continue to live like this in the ninth inning — if, unlike last night, they find themselves in meaningful ninths.